Have searched but could not find...Anyone know which fuse controls the back lighting of the instrument cluster?

Was messing with the sun roof switch because the sun roof opened on its own when I started the car (without me touching the switch). Bypassed the switch to get the sun roof closed but during the troubleshooting, I did something and the dash lights (back lighting) no longer work.

All the gauges and warning lights still work and the Odometer and gear indication on the instrument panel work but no back lighting. I'm assuming it's a fuse but cannot figure out which one. Tried checking a couple which seem likely but didn't find a bad fuse, yet.

Any help would be appreciated. Thanks, Sam

 

This is disappointing that no one has answered this, my dash lights just did this on my way home. They were working last night. Went out just now and found that they're out, same as yours, all other components work, except the dash lights. My doors switches have light, and the dimmer switch dims the display when I move it up and down, so I know it's working, but no lights.

 

Did you guys try the owners manual? They list two or three pages of fuse block and relay's in the cabin and engine compartment. Hope this helps.

 

Everything I see says its both powered and directly controlled from the BCM. Those are LED lights in the instrument cluster, I have a hard time believing they all took a **** at the same time. Body Control Module most likely is at fault. All interior lighting is controlled through the BCM.

 

Yeah I've searched all the manuals and event went through with a test probe and checked every fuse since there's no listing for dash lights. All the dash lights are completely out. The lights for the door switches are fine, and the information display is ok but no other illumination including steering wheel. Sadly there's no logical explanation for it; haven't done any work recently, so it's not like a new short was caused, nothing has been changed. I'd be ok if one or 2 lights were out but it's everything. I hope it's not directly controlled by the ECM, the last thing I want is to replace a computer just for dash lights.

 

Steering wheel & the instrument cluster are both out? There is a 2 amp fuse for the lights on the steering wheel. Note thats going through the air bag module. I dont **** around w/ anything that has to do w/ the airbags...If you want to hunt around on that curcuit, make sure you know what your doing.

Looks like the traction control light is fed off that same circuit, but before the 2 amp fuse. Is that light working?

 

All the lights are out, except the info display and idiot lights (which have nothing to do with illumination). I checked all the fuses but I'll have another go at them. The airbag isn't that big of a deal to play with, it's actually more difficult to set them off than you'd think. When I was a BMW mechanic our dealership didn't sell used. All trade ins were sent to the auction anyway so we had fun. We were poppin off airbags on trade in vehicles, it takes a lot to get them to go off, we actually had to applied power to the line. I'll check again tomorrow morning, it's got to be something fixable, I've just been too busy to look at it.

 

HVAC is also not lit, but the door switches are lit up? Its all a single feed out of the BCM. Looks like the circuit goes to window switches 1st, then sunroof switch, towhaul, dimmer switch, hvac, etc...

Attaching the rest of that interior lighting schematics... At the top just match up the blue triangle letters from one image to another, (A-A, B-B,...).

 

That's a huge help! Thank you. I just got back home, I'll take a look at it tomorrow morning and see if I can figure it out.

 

Armed with schematics, I dove into the lighting issue today. Found something very interesting. I tested and probed just about everything imaginable; no shorts, no breaks, all good clean lines with low/no resistance. You'd thing think that a former BMW/ASE master technician with a degree in automotive engineering would have less trouble with this, but it just goes to show that sometimes we're TOO MUCH of a technician. While tracing lines I found that the connector on back of the fuse box that the fuse plugs into wasnt making contact. The sheathing was fine but for some reason the wire pulled from the connector. Looked great, but had a gap enough to create an open circuit. I grew up in Detroit, so I'm conditioned to love GM, but sometimes they scare me. What ever happen to "instrument panel" in the labeling? I mean I get it, there is more than just the dash lights on that circuit, but there wasn't even anything in the manual saying TBC 2B was instrument panel. Oops, probably shouldn't give out the secret, now there will be less people getting dealer work for dash light. On that note, if I disappear and don't log in for a while it's because GM bumped me off for giving out information that the dash panel lights are connected to the TBC 2B fuse and the wiring behind the fuse panel can become faulty.